Deadliest catch

When the crew of the ESS Pursuit dredged the ocean 72 kilometres off Long Island, New York state, they found more than the clams they sought: they caught 10 artillery shells stamped with dates from World War I.
By Amber Angelle

When one canister broke open, the contents – later identified as mustard gas – blistered one man’s arm and leg, while other crew members suffered from eye and nose irritation. According to army records, the US government sank about 30 000 tons of chemical agents, plus conventional weapons, off that country’s coast between 1917 and 1970, when the practice stopped. “We don’t see a big influence on the surrounding environment,” says the University of Hawaii’s Margo Edwards, who in 2010 completed a comprehensive study of chemical munitions in deep water. “But they’re continuing to deteriorate at an unknown rate. What happens later?” To be prepared, the US army this year purchased a remotely operated vehicle (ROV) that can safely collect discarded weapons from the seafloor. The ROV uses cameras and a laser measuring system to identify ordnance, two arms to manipulate the weapons and compartments that protect operators from contaminants. The army plans to deploy the robot next year for a three-week field test off Oahu, Hawaii.